A076770 Even numbers representable as the sum of two odd composites.

18, 24, 30, 34, 36, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148

Offset: 1

Author

Jon Perry, Nov 14 2002

Keywords

• nonn

Comments

If n is even and n > 38, at least one of (n-15), (n-25), (n-35) is an odd number divisible by 3 and greater than 3. So every even number > 38 is a term. [Jack Brennen]

Examples

			40 can be represented as 15+25 where 15 and 25 are both composite numbers, so 40 is a term.
		

Crossrefs

Cf. A118081.

Programs

PARI

v=vector(5000); vc=1; forstep (n=9,300,2, if (isprime(n),continue, forstep (j=9,300,2,if (isprime(j),continue,x=n+j; fl=true; for (i=1,vc,if (v[i]==x,fl=false; break)); if (fl==true,v[vc]=x; vc++))))); print(vc); v=vecsort(vecextract(v,concat("1..",vc-1)))

Extensions

Corrected by Don Reble, Nov 20 2006